1. Field of the Invention
The present invention relates to a serial bidirectional data transmission method for communication between a programming device and a service device which is to be programmed, such as a hearing aid.
2. Description of the Prior Art and Related Application
Serial, bidirectional data transmission is known for communication between a programming device and a hearing aid device, wherein data and clock pulses are transmitted from the programming device to the hearing aid device for individually adjusting auditory environment-specific data, or hearing deficiency-specific data, of the hearing aid device. It is known to accomplish such transmission using a single signaling line for the data transmission, with variable clock pulses being supplied to the signaling line. The digital information is recovered at the hearing aid device by analyzing the variation in the clock pulses. The recovered digital information is subsequently processed with the transmitted clock pulse. It is known to employ clock pulsewidth variation as the clock pulse variation.
German OS 196 51 126, corresponding to co-pending U.S. application Ser. No. 08/984,060, filed Dec. 3, 1997 (xe2x80x9cSerial Bidirectional Data Transmission Method and Apparatus and Hearing Aid Employing Same,xe2x80x9d W. Meyer), assigned to the same Assignee (Siemens AG) as the present application, teaches a serial, bidirectional data transmission method for communication between a programming device and a service device, wherein for data transmission variably formed clock pulses are applied to a signaling line, and the digital information is recovered by means of clock pulse variation. As an example of a clock pulse variation, a clock pulse amplitude variation is suggested, which, however, can be realized only with considerable technical outlay in a realization of a wireless transmission path between a programming device and a service device.
An object of the present invention is to provide a method for data transmission of the type initially described which is also suitable for wireless data transmission between a programming device and a service device.
The above object is achieved in accordance with the principles of the present invention in a serial, bidirectional data transmission method of the type initially described, wherein a transmission frame with a defined pulsewidth is used, the transmission frame having a start bit which is set to 0 and a stop bit which is set to 1. In the data transmission from the programming device to the hearing aid device, the transmission frame has at least one other bit position, besides the start bit, which is set to 0, this at least one other position being set to 1 in the responsive (answerback) data transmission from the hearing aid device to the programming device. Additionally or alternatively, the responsive data transmission may have at least one other bit position besides the stop bit which is set to 1, this at least one other being positioned being set to 0 in the responsive data transmission from the hearing aid device to the programming device.
Compared to the cited data transmission described in German OS 196 51 126, and U.S. application Ser. No. 081984,060, the inventive data transmission method enables a simplified data transmission, particularly given the use of a wireless transmission path between a programming device and a service device, since a transmission of different signal amplitude information, which is susceptible to interference, is not used.
The overall disclosure of the aforementioned co-pending U.S. application Ser. No. 08/984,060 is incorporated herein by reference. The inventive data transmission method can be expanded by suitable methodological and/or circuit variants described in U.S. application Ser. No. 08/984,060.
For reasons of cost, a standardized serial interface, particularly an RS232 interface, is utilized in the inventive method.
For simpler processing of the clock pulse information, a transmission frame with a defined pulsewidth (particularly 8 bit positions) is advantageously used.
The start of a transmission frame is specified by a start bit that is set at 0, thereby generating the chronological zero point of the transmission frame and making it possible to forgo a separate clock line. The end of a transmission frame can be indicated by a stop bit that is set at 1.
Within the transmission frame, only a certain number of neighboring bit positions are set at 0, and the remaining bit positions are set at 1, so that a pulsewidth signal with an assigned significance is produced. By changing the number of neighboring bit positions that are set at 0 or 1, respectively, different significance assignments can be coded within a transmission frame.
In another variant of the method, in the data transmission from a programming device to a service device, the transmission frame has at least one other bit position (besides the start bit) which is set to 0, or has at least one other bit position (besides the stop bit) which is set to 1. In the transmission back from the service device to the programming device, response information can be inserted in the transmission frame at this additional location. A transmission frame such as TXD and RXD frame is used.
A known interface can be connected between the programming device and the service device, particularly the hearing device, by which interface a voltage level matching between the interface of the programming device and the hearing device can occur, for example. Furthermore, increased programming voltages (e.g. 15V) and answerback signals can be generated via the interface. In addition, in programming of a hearing device which is a dual device, a changeover between the left and the right hearing aids can occur via the interface.